Profiler improvements
* Add events for CUDA kernel start and end.
* Allow network plugins to generate profiling events
* Enable profiling on a per-operation basis, rather than per-communicator.
* Add support for graph capturing.
Add implicit launch order
* Allow to prevent deadlocks when using multiple NCCL communicators per
device by implicitly ordering NCCL operations using the host program
order. Disabled by default, set NCCL_LAUNCH_ORDER_IMPLICIT=1 to enable.
* Add a complementary mechanism to detect host threads racing to launch
to the same device. Enabled by default, set NCCL_LAUNCH_RACE_FATAL=0 to
disable.
Optimize the PAT algorithm
* Separate the computation and execution of PAT steps on different warps,
allowing to run up to 16 PAT steps in parallel to significantly
accelerate PAT and reduce its linear part.
Add support for setting QoS per communicator
* Add a new trafficClass field to the communicator configuration, to
allow the application to select a particular traffic class for a
given communicator. The meaning of the traffic class is
network-specific and should be set in accordance with the network
configuration.
* For the IB/RoCE plugin, existing config variables such as NCCL_IB_SL
and NCCL_IB_TC take precedence.
Allow to enable GPU Direct RDMA specifically on C2C platforms
* Disabled by default, set NCCL_NET_GDR_C2C=1 to enable.
Do not disable user buffer registration unless PXN is really used
* Only disable UB when a communicator has more than one rank per
node on any node.
RAS subsystem improvements
* Report operation counts separately for each collective operation type.
* Provide details about missing communicator ranks and reliably
distinguish ranks that are no longer a given communicator's members
(now reported as NOCOMM) from those that failed to respond.
Add support for timestamps to NCCL diagnostic messages
* On by default for WARN messages; NCCL_DEBUG_TIMESTAMP_LEVELS can be
used to enable them for other debug levels as well.
* The format can be changed using the NCCL_DEBUG_TIMESTAMP_FORMAT config
variable.
Reduce the memory usage with NVLink SHARP (NVLS)
* Potentially save hundreds of MBs of device memory, considering the
multicast buffer size granularity separately from the address alignment.
Update performance tuning for recent Intel CPUs
* Improve algorithm/protocol selection on recent CPUs such as Emerald
Rapids and Sapphire Rapids.
Improve channel scheduling when mixing LL and Simple operations.
* Make LL operations account for 4x more traffic to ensure LL and simple
operations complete at the same time.
Refactor the plugin code
* Clean up and harmonize the support code across the network, tuner,
and profiler plugins.
Add support for comment lines (starting with #) in the nccl.conf file
* Issue #1540.
Make user buffer registration problems print an INFO instead of a WARN.
Drop support for network plugin interface version 5.
Fix a race condition with split-shared communicators
* NCCL could hang during connection setup if multiple communicators
were grouped together that share resources.
Fix a performance regression when using NCCL_CROSS_NIC=1
* NCCL would unnecessarily alternate rings, breaking the GPU-NIC
associations.
Make GID index detection code more resilient
* Dynamic GID detection code was giving up too soon if the
detected index was not available (e.g., wasn't mapped to the
container's sysfs).
* Issues #1538, #1573.
Fix a race condition with non-blocking operation
* Fix issue when creating a non-blocking communicator after a non-
blocking collective operation on another communicator.
Fix shared memory usage on recent Blackwell GPUs.
* Issues NVIDIA/nccl-tests#287, NVIDIA/nccl-tests#291, #1637.
Fix an error with NIC fusion and IB SHARP when recreating communicators
* Disable the unloading of network plugins
Make the auto-merge failures in the NIC fusion non-fatal
* This could happen when trying to merge IB and RoCE devices.
Fixes to ncclCommAbort
* Fix hangs due to the progress thread spinning indefinitely on the
network progress.
* Reduce the abort time by up to two orders of magnitude.
Fix a crash when libnccl.so was dynamically unloaded
* The RAS subsystem was missing a clean-up handler.
Fix a hang if the network plugin's test() call returns an error.
Fix a hang on heterogeneous architectures
* Ensure we harmonize the tuning to avoid different tuning choices,
causing a hang.
Fix double-free on failed ncclCommInitRank and ncclCommFinalize.
Fix a potential list traversal bug during a group launch of multiple
communicators
* Issue #1599.
Unify the handling of NCCL configuration variables
* Under rare circumstances, some variables specified in the config file
could be ignored.
* Fix collective trace
* Use nontemporal for st_global
* Fix previous commit
* Add HDP flush to data receive path
* Fix previous commit
* Control flushing by NCCL_NET_FORCE_FLUSH and RCCL_NET_HDP_FLUSH
* Introduce RCCL_NET_HDP_FLUSH and RCCL_NET_GDR_FLUSH
Both are on by default. Turn both off will skip all flush will likely
result in data error.
* Enable GDR copy by default
* Remove GDR flush env var because it is disabled by GDC flush
* Output kernel collective trace at comm destroy by default
* Limit kernel timeout messages to 100
* Use system relaxed atomic for loadInt
* Refine timeout messages and use atomic for setting offset from CPU
* Add kernel trace for barrier timeout
* Add backup barrier to avoid race in atomicAdd
* Use different counters for different warps
* Rework barrier implementation
* Fix for other GFX
* Use __hip_atomic_store and __hip_atomic_load
* Fix bug in previous commit
* Don't reset barrier values in running kernel
* Update trace format
* Fix typo
* Switch back to hip_atomic_fetch_add
* Use same barrier implementation for all GFX
* Remove extra threadfence
* Turn off HDP flush by default
Please use RCCL_NET_HDP_FLUSH=1 to switch on HDP flush
* Remove unnecessary changes from alterative barrier implementation
* Added back __threadfence_block
* Revert back to threadfence for gfx other than gfx94x
Add Blackwell/SM100 support
* Add compilation for sm100
* Add graph search speeds for Blackwell
* Optimize graph search to converge on large NVLink domains
* Limit NVLS heads to 32
* Increase various limits to fit large NVLink domains
* Add extra checks for IMEX setup, needed for MNNVL
* Increase MAXCHANNELS to 64
Extend NVTX instrumentation to track NCCL communicators
* Add communicator ID to NVTX traces to allow for correlation
between ranks.
RAS fixes
* ext-src: add MSCCLPP memory registration APIs
* update mem-reg patch with mscclpp helper routine to check if buffer is registered
* RCCL integration of MSCCL++ user-buffer registration APIs
* only include mscclpp_nccl header if ENABLE_MSCCLPP is defined
* ext-src: update mscclpp mem-reg patch
* add helper routine to patch
* check handle before MSCCL++ deregister
* fix typo to replace send buff with recv buff
* in case of no mscclpp registration, dduring deRegister call, ont fall back to rccl deRegister which will return an error
* Apply suggestions from code review
Whitespace suggestions and reducing diffs to avoid future merge conflicts
Co-authored-by: corey-derochie-amd <161367113+corey-derochie-amd@users.noreply.github.com>
* rename helper functions and change their return type
* set RCCL user-buffer registration to occur if attempting MSCCL++ registration with a buffer in managed memory
---------
Co-authored-by: isaki001 <Ioannis.Sakiotis@amd.com>
Co-authored-by: isaki001 <36317038+isaki001@users.noreply.github.com>
Co-authored-by: corey-derochie-amd <161367113+corey-derochie-amd@users.noreply.github.com>
Network user buffer support for collectives
* Leverage user buffer registration to achieve zero-copy
inter-node communications for Ring, NVLS and Collnet
Add RAS subsystem
* Create a RAS thread keeping track of all NCCL communicators.
* Add a ncclras tool contacting the RAS thread and getting a
report.
Add fp8 support
* Add support for e5m2 and e4m3 8-bit floating point operations.
* Use Tree/PAT algorithms when possible for better numerical
stability.
Add NIC fusion
* Add a NET API to ask the network plugin to fuse a set of
interfaces together.
* Fuse multiple NICs under the same PCI switch as a single,
larger NIC.
Socket connection failure retry
* Retry in case of socket connection failure (unreachable host)
* Avoid "Software caused connection abort" errors on retries
QP connection failure retry
* Retry in case of IB QP connection failure during ibv_modify_qp.
NET API improvements
* Allow plugins to force a flush in case data and completion
ordering is not guaranteed.
* Indicate when completion is not needed (e.g. for the LL128
protocol), allowing plugins to skip generating a completion.
* Allow for full offload of allgather operations when using one
GPU per node.
NCCL_ALGO/NCCL_PROTO strict enforcement
* Extend NCCL_ALGO/NCCL_PROTO syntax to be able to specify
ALGO/PROTO filters for each collective operation.
* Strictly enforce the ALGO/PROTO filters, no longer fall back
on the ring algorithm when the filtering leaves no option and
error out instead.
Enable CUMEM host allocations
* Use cumem functions for host memory allocation by default.
Improved profiler plugin API
* Avoid dependencies with NCCL includes.
* Add information on whether the buffer is registered or not
Adjust PAT tuning
* Improve transition between PAT and ring at scale.
Fix hangs when running with different CPU architectures
* Detect when we use a mix of GPU architectures
* Ensure Algo/Proto decisions are made based on that unified
state.
Fix FD leak in UDS
* Fix a leak when mapping buffers intra-node with cumem IPCs.
Fix crash when mixing buffer registration and graph buffer registration.
* Separate local and graph registration to avoid crashes when we free
buffers.
Fix user buffer registration with dmabuf
* Make ncclSend/ncclRecv communication with buffer registration functional
on network plugins relying on dmabuf for buffer registration.
Fix crash in IB code caused by uninitialized fields.
Fix non-blocking ncclSend/ncclRecv
* Fix case where ncclSend/ncclRecv would return ncclSuccess in non-blocking
mode even though the operation was not enqueued onto the stream.
* Issue #1495
Various compiler tweaks and fixes
* PR #758
Fix typo in ncclTopoPrintGraph
* Issue #1468
Add scalable init API
* Add new ncclCommInitRankScalable to allow for passing multiple
unique IDs to the init function.
* Spreads the load onto multiple bootstrap roots, allowing for
constant bootstrap time.
* Requires multiple ranks to create a unique ID, and the CPU-side
ID exchange code to call allgather[v] instead of broadcast.
Accelerate init bootstrap operations
* Reduce the number of calls to allgather.
* Allow roots to reply early to ranks when information is already
available.
* Add an option to use ncclNet instead of sockets to perform
bootstrap allgather operations.
Add PAT algorithms for Allgather and ReduceScatter
* Parallel Aggregated Trees, variation of Bruck algorithm.
* Logarithmic number of network steps for small sizes at scale.
* Only supports one rank per node at the moment.
Add support for registered buffers for intra-node communication.
* Allow registered user buffers to be accessed directly intra-node
* Avoids extra copies in algorithms which permit it, saving
memory bandwidth and helping with compute overlap.
Add profiler plugin API
* New plugin API for profiling
* Supports various levels of profiling, with a hierarchy.
Asynchronous graph allocation
* Make calls to cudaMalloc and cudaMemcpy during graph allocation
asynchronous.
* Significantly speeds up graph capture.
Use fatal IB asynchronous events to stop network operation
* Avoids many other error messages
* Only fatal errors are affected; potentially transient errors
(e.g. port down) do not cause an immediate stop.
Set P2P level to PXB on AMD CPUs when using more than 2 GPUs per node
* P2P would cause a significant performance degradation when using
many GPUs, and therefore many interleaved data flows.
* Disable P2P through the CPU when we have 3+ GPUs per node; keep it
enabled when we only have 2 GPUs.
Improve the init logs to report the real NCCL function.
* Make the log report ncclCommInitRank or ncclCommSplit, rather than
the generic ncclCommInitRankFunc.
Add a parameter to set the location of the user configuration file.
* Add NCCL_CONF_FILE environment variable to set where the user's
configuration file resides.
Increase default IB timeout
* Increase IB timeout value from 18 to 20.
* Should help avoid fatal errors on large RoCE systems.
Add new check for nvidia peermem
* On linux kernels 6.6+, /sys/kernel/mm/memory_peers is no longer
present; check for /sys/module/nvidia_peermem/version instead.
Fix old performance regression when mixing small and large operations.
* Improves distribution of work on channels.
Fix crash when NUMA IDs are equal to -1.
* Can happen when a NIC is a virtual NIC, or when linux doesn't
know which NUMA node a device is attached to
* Issue NVIDIA/nccl-tests#233
Fix tree graph search when NCCL_CROSS_NIC is set to 1.
* Would force NCCL to use the balanced_tree pattern, thereby
disabling LL128 on platforms with 1 GPU+1 NIC per PCI switch.
* Would also try to use alternate rings even though it was not
needed.
Compiler tweaks and fixes
* PR #1177
* PR #1228
Fix stack smash
* PR #1325
Fixes for multi-node NVLink + IB operation
Coverity fixes and comments.
* Moved call to `mscclpp_ncclGetUniqueId` into `ncclCommInitRankFunc` to avoid setting up transport early in environments where MSCCL++ isn't valid.
* Checking `mscclEnabled` for the process and the topology to gate MSCCL++.
* Allowed `mscclForceEnable` to enable MSCCL++.
* Added restrictions around calling MSCCL++ collectives (#1281)
* Added restriction to non-zero 32-byte multiple message sizes to MSCCL++ AllGather.
* Renamed and refactored some mscclpp types.
* Only transmit the MSCCL++ unique id for non-split comm init. For splitting comm, it has already been transmitted. Instead, save the MSCCL++ communicator in child communicators when calling `ncclCommSplit`. Only destroy MSCCL++ communicators when no RCCL communicators remain that use it. Also improved trace logging.
* Disable MSCCL++ when using managed memory buffers as it isn't supported.
* Added datatype and op constraints for MSCCL++ AllReduce.
* Added documentation on MSCCL++ restrictions to the README.
* [BUILD] Support custom CMake flags in MSCCLPP (#1275)
* [BUILD] Support custom CMAKE_PREFIX_PATH in MSCCLPP
Signed-off-by: nileshnegi <Nilesh.Negi@amd.com>
* [BUILD] CMake flags to support build-id in MSCCLPP
Signed-off-by: nileshnegi <Nilesh.Negi@amd.com>
* [BUILD] Fix CMake warnings in MSCCLPP build
Signed-off-by: nileshnegi <Nilesh.Negi@amd.com>
* Wrapped all cmake arguments passed to mscclpp to remove empty arguments and properly format them.
---------
Signed-off-by: nileshnegi <Nilesh.Negi@amd.com>
Co-authored-by: Corey Derochie <corey.derochie@amd.com>
* Link to libmscclpp_nccl statically (#1282)
* Switched mscclpp_nccl to static linking. Added a build step to rename the NCCL API functions.
* Undid separation of building libmscclpp_nccl from building librccl with MSCCL++ integration. With a static build, it's either fully enabled or fully disabled.
* `nm` isn't always available in docker containers due to being stripped down. Removed use of `nm` in `cmake` and hard-coded the output into mscclpp_nccl_syms.txt.
* Removed IBVerbs dependency for integrating with MSCCL++ (#1313)
* Renamed `RCCL_ENABLE_MSCCLPP` to `RCCL_MSCCLPP_ENABLE` to conform to MSCCL. Set `RCCL_MSCCLPP_ENABLE` to 1 by default if `ENABLE_MSCCLPP` is defined, or 0 otherwise. Added a log warning if `RCCL_MSCCLPP_ENABLE` is set to 1 but `ENABLE_MSCCLPP` is not defined. (#1294)
* Include mscclpp as a git submodule (#1314)
* Added the desired mscclpp commit as a git submodule.
* Added step to automatically checkout the mscclpp submodule if it isn't already present, in case the user forgot to clone recursively.
* Added instruction to README to clone using --recurse-submodules to get the mscclpp submodule.
* Enabled MSCCL++ feature build.
---------
Signed-off-by: nileshnegi <Nilesh.Negi@amd.com>
Co-authored-by: Nilesh M Negi <Nilesh.Negi@amd.com>
* adding all nccl apis to api_support to enable rccl tracing by rocprofv3
Co-authored-by: Marzieh Berenjkoub <mberenjk@amd.com>
Co-authored-by: Jonathan R. Madsen <jonathanrmadsen@gmail.com>
MSCCL can now run in a multi-threaded configuration. To test in the unit tests, added the ENABLE_OPENMP compile definition flag and the --openmp-test-enable flag to the unit test build script. To activate, set the environment variables UT_MULTITHREADED=1 and UT_PROCESS_MASK=1. Set Jenkins to use this mode.
Rework core for NVIDIA Trusted Computing
* Compress work structs so that they are shared between channels
* Utilize the full amount of kernel argument space permitted (4k)
before resorting to work fifo.
* Rework the task preprocessing phase.
* Use a separate abortDevFlag which is kept in sync with abortFlag
using cudaMemcpy operations.
* Rename src/include/align.h to src/include/bitops.h
Add lazy connection establishment for collective operations
* Move buffer allocation and connection establishment to the first
collective operation using that algorithm.
* Accelerate init time and reduce memory usage.
* Avoid allocating NVLS buffers if all calls are registered.
* Compute algo/proto in ncclLaunchCollTasksInfo early on.
* Connect peers in ncclCollPreconnectFunc if not connected already.
* Also move shared buffer creation to the first send/recv call.
Accelerate intra-node NVLink detection
* Make each rank only detect NVLinks attached to its GPU.
* Fuse XMLs to reconstruct the full NVLink topology
Add init profiling to report time spend in different init phases.
* Report timings of bootstrap, allgather, search, connect, etc.
* Add new "PROFILE" category for NCCL_DEBUG_SUBSYS.
Add support for PCI p2p on split PCI switches
* Detect split PCI switches through a kernel module exposing
switch information.
* Update the topology XML and graph to add those inter-switch
connections.
Add cost estimation API
* Add a new ncclGroupEndSimulate primitive to return the estimated
time a group would take.
Net/IB: Add separate traffic class for fifo messages
* Add NCCL_IB_FIFO_TC to control the traffic class of fifo messages
independently from NCCL_IB_TC.
Merges PR #1194
Net/IB: Add support for IB router
* Use flid instead of lid if subnets do not match
* Warn if flid is 0
Optimizations and fixes for device network offload (unpack)
* Double the default number of channels
* Cache netDeviceType
* Fix save/increment head logic to enable Tree support.
Support ncclGroupStart/End for ncclCommAbort/Destroy
* Allow Abort/Destroy to be called within a group when managing
multiple GPUs with a single process.
Improve Tuner API
* Provide to the plugin the original cost table so that the plugin
can leave unknown or disabled algo/proto combinations untouched.
* Remove nvlsSupport and collnetSupport.
Do not print version to stdout when using a debug file
* Also print version from all processes with INFO debug level.
Fixes issue #1271
Fix clang warnings in NVTX headers
* Update NVTX headers to the latest version
Fixes issue #1270
Disable port fusion in heterogeneous systems
* Do not fuse ports if a mix of multi-port and single port are detected.
Fix NVLS graphs search for dual NICs.
* Fix NVLS graph search when we have more than one NIC per GPU.
Fix crash with collnetDirect
* Add separate graph search for collnetDirect, testing alltoall paths
and working similarly to the NVLS search.
Fix hang when nodes have different CPU types
* Add the CPU type to the rank peer info.
* Align all ranks on the CPU type after the first allgather.
* Only use the aligned CPU type for all tuning operations.
Fixes issue #1136
Fixes issue #1184
Fix performance of registered send/recv operations
* Allow for single full size operations
* Add INFO to confirm the registration of send/recv buffers.
Move all sync ops to finalize stage
* Ensure ncclCommDestroy is non-blocking if ncclCommFinalize has
been called.
Improve error reporting during SHM segment creation
Improve support of various compilers
Merges PR #1177
Merges PR #1228
Allow net and tuner plugins to be statically linked
* Search for ncclNet or ncclTuner symbols in the main binary.
Merges PR #979
Plugin examples includes cleanup
* Harmonize err.h and common.h usage.
* Add mixed plugin with both net and tuner.
Kamil Iskra
Nusrat Islam
Wenkai Du
Bertan Dogancay
Pedram Alizadeh
corey-derochie-amd
mberenjk
Mustafa Abduljabbar
Arm Patinyasakdikul
Sylvain Jeaugey
BertanDogancay
isaki001
Dingming Wu
Xeonacid
akolliasAMD
Rahul Vaidya
Edgar Gabriel
Nilesh M Negi